| ( | 200 | + | 200 | a | ) | ( | 150 | ( | - | 10 | ÷ | 9 | × | a | ) | ) | = | 20000 |
| Left side of the equation = | 200 | ( | 150 | ( | - | 10 | ÷ | 9 | × | a | ) | ) | + | 200 | a | ( | 150 | ( | - | 10 | ÷ | 9 | × | a | ) | ) |
| = | 200 | × | 150 | ( | - | 10 | ÷ | 9 | × | a | ) | + | 200 | a | ( | 150 | ( | - | 10 | ÷ | 9 | × | a | ) | ) |
| = | 30000 | ( | - | 10 | ÷ | 9 | × | a | ) | + | 200 | a | ( | 150 | ( | - | 10 | ÷ | 9 | × | a | ) | ) |
| = | - | 30000 | × | 10 | ÷ | 9 | × | a | + | 200 | a | ( | 150 | ( | - | 10 | ÷ | 9 | × | a | ) | ) |
| = | - | 100000 3 | a | + | 200 | a | ( | 150 | ( | - | 10 | ÷ | 9 | × | a | ) | ) |
| = | - | 100000 3 | a | + | 200 | a | × | 150 | ( | - | 10 | ÷ | 9 | × | a | ) |
| = | - | 100000 3 | a | + | 30000 | a | ( | - | 10 | ÷ | 9 | × | a | ) |
| = | - | 100000 3 | a | − | 30000 | a | × | 10 | ÷ | 9 | × | a |
| = | - | 100000 3 | a | − | 100000 3 | a | a |
| - | 100000 3 | a | − | 100000 3 | a | a | = | 20000 |